The writer and broadcaster Victoria Coren wrote in The Observer yesterday that commuters at Bath railway station had recently been “instructed to walk through a 7ft body scanner”:

Since when did we surprise the public with electronic body searches, randomly as they go about their daily lives, without any reason to suspect them of anything? Have search warrants also been abandoned while I wasn’t looking? May the police now turn up on a whim and rootle around in our drawers?

These are serious and current concerns. The use of Advanced Imaging Technology (or AIT) at airports is not without controversy. However, the rolling-out of this technology to other areas, for instance railway stations, would be a major development, and it would raise great concern if it was done without publicity, consultation, and without there being clear reasons for its use. However, the American blogger and privacy activist who goes by the twitter handle of @PogoWasRight has spotted this press release on Avon and Somerset Constabulary’s website, which suggests that in fact what Coren experienced was a metal detector designed primarily to pick up people carrying hidden knives:

The police operation will see people arriving by train being screened by an airport-style metal detector to see if they are carrying knives or other weapons.

These are commonly known as “knife-arches” and are essentially the same metal detector arches we are accustomed to passing through at airports. They are a considerably less intrusive technology than AIT, although their use is not in itself without controversy